Handheld device having multiple nfc reading directions

ABSTRACT

A handheld device includes at least two NFC antennas provided with different RF transmission directions. The at least two NFC antennas are separated from each other and share one communication unit. In light of this, the handheld device exchange data with an external NFC device through the at least two NFC antennas to have more effective inductive coupling directions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a handheld device and moreparticularly, to a handheld device having multiple near-fieldcommunication (NFC) reading directions.

2. Description of the Related Art

As the NFC antenna is developed, more and more handheld devices, such asmobile phones, are equipped with the NFC antennas to function aselectronic tags or simulated credit cards. A conventional NFC antenna isusually mounted to an inner side of a back cover of the handheld device.Therefore, when a user intends to proceed with the service, such assimulated credit card, the user needs to aim the back cover of thehandheld device at an external NFC device to make the NFC antennainductively coupled with the external NFC device for data exchange. Inthe process of each data exchange, the user needs to make the NFCantenna face the same direction for inductive coupling with the externalNFC. However, every user has his or her own custom and need and if thehandheld device can provide different directions for inductive coupling,the operational convenience could be enhanced for the user.

In addition, back covers of some handheld devices are made of metal forthe purpose of high-quality perception and design as a whole. Themetallic back covers can though boost the thermal dissipation of thehandheld device, but they lead to interference with the NFC antennainductively coupled with the external NFC device for data exchange.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a handhelddevice which can be inductively coupled with signals of various radiofrequency (RF) transmission directions, respectively, to further havemore effective inductive coupling directions.

The foregoing objective of the present invention is attained by thehandheld device comprising a communication unit, a first NFC antenna,and a second NFC antenna. The communication unit includes an input endand an output end and is connected with a first circuit and a secondcircuit in parallel. The first NFC antenna is mounted to the firstcircuit. The second NFC antenna is mounted to the second circuit and isprovided with an RF transmission direction different from that of thefirst NFC antenna. The equivalent inductance between the input andoutput ends matches the communication unit.

The first and second NFC antennas are separated from each other in thehandheld device and their RF transmission directions are different fromeach other, so more effective inductive coupling directions are enabledfor the handheld device to exchange data with an external NFC device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a first preferred embodiment of thepresent invention.

FIG. 2 is an equivalent circuit diagram of an NFC antenna through thecommunication unit in accordance with the first preferred embodiment ofthe present invention.

FIG. 3 is an exploded view of the first preferred embodiment of thepresent invention, illustrating the locations of the first, second, andthird NFC antennas.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Structural features and desired effects of the present invention will bemore fully understood by reference to a preferred embodiment givenhereunder. However, it is to be understood that the embodiment is givenby way of illustration only, thus being not limitative of the claimscope of the present invention.

Referring to FIGS. 1-3, a handheld device having multiple NFC readingdirections constructed according to a first preferred embodiment of thepresent invention is formed of a first NFC antenna 10, a second NFCantenna 20, and a communication unit 30 electrically connected with thefirst and second NFC antennas 10, 20. The handheld device can be amobile phone, a tablet computer, or an equivalent device. In thisembodiment, the handheld device is a mobile phone 1 as an example andthe present invention recited hereunder is based on the direction that ascreen 60 of the mobile phone 1 faces forward. The detailed descriptionsand operations of these elements as well as their interrelations arerecited in the respective paragraphs as follows.

Referring to FIG. 1 again, the first NFC antenna 10 is a coil-woundantenna made of copper foil, surrounding and mounted to a carriersurface 12 of a carrier 11. A third NFC antenna 40 is mounted to acenter of the carrier surface 12 and formed of a coil for matching thefirst NFC antenna 10. Both of the first and third NFC antennas 10, 40are mounted to the carrier 11, so the limited space inside the mobilephone can be less occupied

The second NFC antenna 20 is a winding-type inductive antenna and woundaround a bar-shaped strut 21. The second NFC antenna 20 is connectedwith the third NFC antenna 40 in series and then both are connected withthe first NFC antenna 10 in parallel.

The communication unit 30 is an NFC chip and mounted to a main board(not shown), having an input end A and an output end B. The idealequivalent circuit of an NFC antenna is an inductor, referring to FIG. 2for an equivalent circuit diagram of the NFC antenna through thecommunication unit 30. The first NFC antenna 10 is mounted to a firstcircuit C1. The second and third NFC antennas 20, 40 are mounted to asecond circuit C2 in a way that the second and third NFC antennas 20, 40are connected in series. The communication unit 30 can transmit acommunication signal to an external NFC device N, as shown in FIG. 3,outside the mobile phone 1 through the first and second NFC antennas 10,20. And the communication unit 30 can also receive an input signalinductively coupled by the first NFC antenna 10 or the second NFCantenna 20 through the external NFC device N to make the mobile phone 1actively or passively exchange data with the external NFC device N.

In this embodiment, the inductance of an NFC antenna to which thecommunication unit 30 needs to match is 4.7 μM. An inductance L1 of thefirst NFC antenna 10 is 9.4 μH. An inductance L2 of the second NFCantenna 20 is 4.7 μH. An inductance L3 of the third NFC antenna 40 is4.7 μH. After the second and third NFC antennas 20, 40 are connected inseries, the total inductance is 9.4 μH and the second and third NFCantennas 20, 40 are connected with the first NFC antenna 10 in parallelto make the equivalent inductance of the first NFC antenna 10 in theequivalent circuit be regarded as 4.7 μM. Therefore, the first NFCantenna 10 can match the communication unit 30 and in this way, thecommunication unit 30 can drive the first and second NFC antennas 10, 20at the same time. In light of this, the user can optionally make thefirst NFC antenna 10 or the second NFC antenna 20 of the mobile phone 1inductively coupled with the input signal emitted by the external NFCdevice N.

Referring to FIG. 3 again, the mobile phone 1 includes a housing 50 anda rear shell 51, both of which can be combined with each other. Thecarrier 11 is mounted between the rear shell 51 and a battery 70, so theRF transmission direction of the first NFC antenna 10 is backward. Thesecond NFC antenna 20 is mounted to a corner of the rear shell 51 andadjacent to a top side and a lateral side 52 of the read shell 51. Thestrut 21 is substantially perpendicular to the top side of the rearshell 51, so the RF transmission direction of the second NFC antenna 20is upward.

In operation, the first and second NFC antennas 10, 20 are located atdifferent positions inside the mobile phone 1, so the RF transmissiondirections of the first and second NFC antennas 10, 20 are differentfrom each other. When the user intends to operate the mobile phone 1 toexchange data with the external NFC device N, the user can aim the topside of the mobile phone 1 at the external NFC device N or aim a rearside of the rear shell 51 at the external NFC device N, so the user canchoose the first NFC antenna 10 or the second NFC antenna 20 for dataexchange with the external NFC device N.

The first NFC antenna 10 or the second NFC antenna 20 can be selectedfor data exchange with the external NFC device N and the RF transmissiondirections of both are different from each other, so the mobile phone 1can have more effective inductive coupling directions for data exchangewith the external NFC device N at multiple angles to enhance theoperational convenience. The first and second NFC antennas 10, 20 sharethe communication unit 30, so the cost can be spared.

It is worth mentioning that in this embodiment, the first NFC antenna 10serves as the primary antenna, the second NFC antenna 20 serves theauxiliary antenna, and the third and second NFC antennas 40, 20 aremounted to the carrier 11 at the same time to make their RF transmissiondirections the same, so the third NFC antenna 40 primarily serves asinductive matching. One of ordinary skill in the art can change theinductance of the second NFC antenna 20, as it actually depends, to makeit identical to that of the first NFC antenna 10, i.e. both are set as9.4 μM. In this way, the third NFC antenna 40 can be omitted and thefirst and second NFC antennas 10, 20 can also match the communicationunit 30.

In addition, one of ordinary skill in the art can pull the third NFCantenna 40 out of the carrier surface 12 to mount the third NFC antenna40 to another position of the mobile phone 1 to make the RF transmissiondirection of the third NFC antenna 40 different from those of the firstand second NFC antennas 10, 20. Therefore, the mobile phone 1 can havemore effective inductive coupling directions.

A handheld device having multiple NFC reading directions constructedaccording to a second preferred embodiment of the present invention issimilar to that of the first preferred embodiment, having the followingdifference. In the second preferred embodiment, the rear shell 51 of ismade of metal and the carrier 11 is attached to a rear side of thescreen 60, so the user can aim a front side of the screen 60 at theexternal NFC device N for data exchange.

It is to be noted that the positions of the first and second NFCantennas 10, 20 are not limited to what are mentioned in aforesaid twopreferred embodiments. For example, one of ordinary skill in the art cantransversally place the second NFC device 20 to make the RF transmissiondirection of the second NFC antenna 20 perpendicular to the lateral side52 of the mobile phone 1. In addition, the second NFC antenna 20 can bechanged to a coil-wound antenna as the same as the first NFC antenna 10.

What is claimed is:
 1. A handheld device having multiple near-fieldcommunication (NFC) reading directions, comprising: a communication unithaving an input end and an output end for connection with a firstcircuit and a second circuit in parallel; a first NFC antenna mounted tothe first circuit; and a second NFC antenna mounted to the secondcircuit and having a radio frequency (RF) transmission directiondifferent from that of the first NFC antenna; wherein an equivalentinductance between the output end and the input end matches thecommunication unit.
 2. The handheld device as defined in claim 1,wherein the first and second circuits have substantial the sameequivalent inductances.
 3. The handheld device as defined in claim 1further comprising at least one third NFC antenna connected with thesecond NFC antenna in series, wherein the RF transmission direction ofthe third NFC antenna is different from that of the first or second NFCantenna.
 4. The handheld device as defined in claim 1 further comprisingat least one third NFC antenna and a carrier, wherein the at least onethird NFC antenna and the first NFC antenna are mounted to a carriersurface of the carrier.
 5. The handheld device as defined in claim 4further comprising a rear shell and a battery, wherein the battery ismounted inside the handheld device and the carrier is mounted betweenthe rear shell and the battery.
 6. The handheld device as defined inclaim 1, wherein the second NFC antenna is mounted inside the handhelddevice and is a winding-type antenna wound around a bar-shaped strut,the strut being longitudinally perpendicular to a top side of thehandheld device.